Transmission linkage for grading machines



March 13, 1951 H. w. CARNES ET AL 2,545,225

TRANSMISSION LINKAGE FOR GRADING MACHINES Filed Aug. 26, 1946 TnVBnTnr5 HERBERT w CARNES amass a. moms E 7/ A Dru Patented Mar. 13, 1951 TRANSMISSION LINKAGE FOR GRADING MACHINES Herbert W. Carnes, Swampscott, and Charles C. Thomas, West Mediord, Mass, assignors to North American Research Corporation, Cambridge, Mass, a corporation of Massachusetts Application August 25, 1946, Serial No. 692,960

This invention relates to grading machines of the general type known as Nichols, Cogswell and Johnston machines for grading leather blanks, such as soles, heel lifts, counters, and other blanks of a similar nature.

, The principal object of the invention is to reduce friction in and generally improve the efficiency of machines of the type herein described and referred to.

Another object is to reduce wear in the journal boxes of the detecting roll and adjacent parts which directly affects the smoothness and accuracy of the grading.

Still another object is to eliminate certain bending stresses now present in the spring which provides a yielding connection between the supporting yoke of the movable detector roll and the transmission lever, so as to maintain at all times a purely axial load on said spring.

Other objects and novel features will be more to the machine disclosed in Patent No. 1,743,320,

dated January. 14, 1930, to Leander A. Cogswell. This machine is typical of those now in use for which the present invention is primarily adapted. Only those parts of the machine which are essential to the understanding of the present invention are shown. In the drawings,

Fig. 1 is a fragmentary central elevation of Fig. 5 of the said Cogswell patent, patricularly showing the improvement in the connecting linkage between the floating detector roll and the transmission'lever, and

Fig. 2 is a cross-section taken on line 22 of Fig. 1 corresponding to Fig. 6 of the above-mentioned Cogswell patent but looking toward the front of the machine.

Referring more in detail to the drawings, the blanks are fed into the machine from a table Ill, between guides I 2, the nearest of which is not shown in Fig. 1, to the feed rolls I3 and I4. 'The upper roll I3 is mounted in journal boxes 'I5--'I5 which are held stationary during the operation of the machine but are vertically adjustable in slideways' on the machine frame by means of screws IG-46, worm gears I'II'I, and worms I8I8 on 'hand shaft IS. Theshaft of lower or detector roll I4, sometimes referred to as a feeler roll, is mounted in journal boxes IDOI00, which slide in the same ways on the frame as the upper journal boxes I 5I5. Journal boxes Hill- I90 are "fastened 'toyoke I30. Spring I I0, "acting through 6 Claims. (01. 33-147) *wear in the slideways and journa1 boxes.

2 levers I20l20 and yoke I30, yieldingly urges detector roll Is toward stationary roll I3, substantially as shown in the Cogswell patent herein referred to.

The rolls I3 and I l feed the blank forward between a continuously travelling chain I40 and a yielding, spring pressed shoe I50, which presses the blank down firmly into engagement with the chain so that the latter will continue to carry. the blank forward after it leaves the rolls I3 and I4 and present'it to the skiving mechanism (not shown) which skives the blank to the minimum thickness as detected by the roll I4.

The up and down motion of the detector roll It in response to the varyingthickness of a blank is transmitted to a rock-lever I90 hereinafter referred to as the transmission lever. The linkage from the detector roll I4 to the transmission lever I90 comprises the universal connecting rods and spring assembly which is the subject matter of this invention.

Referring first to Figs. 6 and 7 of the Cogswell patent cited herein and usin the reference numerals there shown, it can be seen that transmission lever I9 is there connected to yoke I3 by means of rods 28 which are secured to the yoke by pin joints and extend through holes in lever I9 where their ends are held in place by nuts and washers. Even the slight rotation of .lever I9 about shaft 22 which results from pas.-

sage of a blank through the rolls is sufficient to cause binding in the pin joints, which interferes with the tilting of detector roll 4 to accommodate blanks of uneven thickness. A twist is likewise transmitted through yoke I3 to journal boxes I0, resulting in excessive friction and considerable Considerable bending stress is also developed in the rods. In addition spring 2!, which rests against the underside of yoke I3 and serves to press lever I9 against the washers on rods 20, is subject to bending due to rotation of lever I9. The alteration in spring characteristics thereby resulting adversely affects the accuracy of the grading. To eliminate these difficulties the connecting rod and spring assembly shown in the Cogswell patent has been replaced with the present invention on machines of this and similar types.

Referring now to Figs. 1 and 2 herein, yoke I30 and transmission leverlllfl corresponding to yoke I3 and lever I9 in Cogswell are connected by rods zoo having hemispherical upper'e'nds 2M, which rest in appropriate sockets in the'yoke.

The lower ends of the rods 200 are provided with adjustmentball nuts 25!? operating in appropriate sockets on the lower'side of the transmission lever I99 better shown in Fig. 2. 'It is evident that free universal movement of rods 2!!!! is thus provided with respect to both the yoke I3Iland transmission lever I90. Twisting of journal boxes II00 in their respetcive slide ways, with the resultin irietion and :wear, is therefore eliminated.

It is apparent that rods 200 serve to restrain lever I90 in the downward direction only, To provide yielding restraint of the lever in the upward direction, a novel spring arrangement is provided. A projection 3I5 on the und r si e of lever I90 accommodates a deep recess, and an opening 320, which is adapted to form a socket for hemispherical member 325. Rod 3I0, the upper end of which is rounded and seats in conical recess 300 on the underside of yoke I30, slides loosely in member 325. Spring 2I0 engages the iiat side of the hemispherical memb'er 325 and is adjusted to the proper tension by means of a washer and retaining nut 330 which is threaded on rod 3H1. Since universal movement is provided for rod 3I0 with respect to yoke I30 and member 325 with respect to lever I90, the rod and hemispherical member 325 tend to adjust their respective positions so as to maintain the load on spring 315 urely axial regardless of the position assumed by yoke I30 and lever I90.

It must be borne in mind that the object of the grading operation is to determine the thickness of the thinnest portion of the blank and transmit this value to an indicating or skiving device so that the entire blank may be cut down to .a corresponding uniform thickness. In the said Cogswell machine, a ratchet and pawl mechanism is put into operation when a blank enters the grading rolls, so as to lock the transmission lever against downward travel. The upward movement of the transmission lever is governed by the position of the movable detector roll, and it is apparent that the highest position assumed by the lever corresponds to the minimum thickness encountered by the rolls. during passage of a blank. Because of the binding of the connecting rod arrangement shown in the 'Cogswell patent, the lower detecting roll is frequently prevented from tilting freely when a blank of tapered cross section is encountered, with the result that the true minimum thickness is not transmitted. With the arrangement disclosed herein, the separable universal joints on both top and bottom of the connecting rods allow the detector roll to tilt freely, raising lever I90 by means of either rod to a position corresponding to the thickness of the thinner side of a tapered blank. It is evident that the new arrangement herein disclosed, by freeing the mo- 'tion of the detector roll, greatly improves the accuracy and efficiency of the machine with a considerable reduction in the percentage of rejects among the blanks after the skiving operation.

Since certain changes may be made in the above-described article and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative only and not in a limitin sense.

7 We claim:

1. In a grading machine of the classdescribed h ving det ct means, includin a floatin r011,

said roll and said lever and universally mcvable with respect to both; and means comprising a compression spring universally seated on said lever and a compression rod universally pivoted with respect to said roll for normally holding said roll and said lever apart to the limit permitted by said linkage.

2. Apparatus according to claim 1 wherein said linkage comprises connecting rods having ball and socket joints at both ends.

3. In a grading machine of the class described having detecting means, including a floating roll,

- for detecting the thickness of material, and a transmission lever adapted to transmit the minimum thickness so detected to other mechanisms; a linkage arranged to limit the separation of said roll and said lever, said linkage comprisin a connecting rod having ball and socke J in at both ends; an a spri g niversal y ounted on said lever and arranged to urg d roll and said lever apart to the limit permitted by said linkage.

A. .lna gradin machine of the class described having detecting means, including a floating roll, for detecting the thickness of material, and a transmission lever adapted to transmit the minimum thickness so detected to other mechanisms, and having a recess; a yoke supporting said roll, said yoke having a conical recess; a linkage arranged to limit the separation of said yoke and said lever; a compression rod having a rounded end which is sea d. in. s id conical reces and carryin a projecting shoulder; a hemi pheri al ball member seated in the recess in said lever; and a coil spring having one end engaged with said shoulder and the other end pressing against the fiat side of said ball member for normally holding said roll and said lever apart to the limit permitted by said linkage.

5. Apparatus according to claim 4 wherein said linkage comprise connecting rods havin ball and socket joints at bQth ends.

6. In a grading machine of the class described having detecting means, including a floatin roll, for detecting the thickness of material, and a transmission lever adapted to transmit the minimum thickness so detected to other mechanisms, and having a recess; a yoke supporting said roll, said yoke having a conical recess; a linkagearranged to limit the separation of said yoke and said lever and universally connected to both; a compression rod having a rounded end which is seated in said conical recess, and carrying a projecting shoulder; a hemispherical ball member seated in the recess in said lever; and a coil spring having one end engaged with said shoulder and the other end pressing against the flat side of said ball member for normally holding said roll and said lever apart to the limit permitted by said linkage- HERBERT W. CARNES. CHARLES C. THOMAS.

REFERENCES CITE!) The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 1,141,396 Jubinville June 1, 1915 1,182,105 Roberts May 9, 1916 1,743,320 Cogswell ;s Jan. 14, 193.0 1,957,432 Barnes i May 8, 1934 2,180,591 Johnston Nov. 21, 1939 2,203,984 Deters June 11, 1940 2,338,28 G ldb urn t alin- Jan. 4, 1944 

